Effect of sintering time on the dielectric properties of CaCu3Ti4O12 using enhanced microwave processing

Abstract

The conventional technique of CaCu3Ti4O12 synthesis involved a very high sintering temperature (>1000°C) and long soaking time (>5h). The high temperature and time-consuming process caused the conventional technique to be inefficient and costly. In this study, the microwave sintering approached was carried out using an enhanced process to solve this problem and the dielectric properties and other properties are investigated. In this study, an enhanced silicon carbide (SiC)-based susceptor was utilized to optimize the microwave radiation temperature towards the CCTO sample. The CCTO samples were prepared using a solid-state reaction route. The X-ray diffraction analysis shows that the phase formation of cubic CCTO formed after the calcination process. The calcination process of CCTO powder was conducted conventionally in a furnace at 900°C for 12 hours. The CCTO cylindrical pellets were then sintered using a commercial microwave at 2.45GHz and 800W power. The sintering process was tested in five different irradiation times: 1 hour, 2 hours, 3 hours, 4 hours, and 5 hours. The electrochemical impedance spectroscopy conducted at 2.5V and 3V with 1Hz to 10MHz of frequency shows the dielectric behaviour performance of the sample concerning sintering time. The result reveals that the dielectric constant was best produced for 5 hours of sintering time. However, the sample can melt beyond the duration because the high heat generated at the sample's interior deteriorated the sample shape. The dielectric loss is also reasonably low between the time. It is then proven that completing the microwave sintering process in 5 hours is sufficient to improve the dielectric properties of the CCTO.